Plasma Etching Chamber

ABSTRACT

Disclosed is an apparatus of dry cleaning a film and particles deposited at a periphery of a wafer. The apparatus comprises a housing providing a space isolated from an outside and having an upper surface opened/closed by a cover; an upper electrode assembly mounted in the housing being separated from the cover so that its position is maintained when opening and closing the cover; a lower electrode assembly mounted below the upper electrode assembly to be moveable vertically in the housing; and means for moving the lower electrode assembly vertically. In addition, transparent observation windows are provided at a center of an upper assembly so that it is possible to check an alignment state of the wafer from the outside.

CROSS-REFERENCES TO RELATED APPLICATIONS

This application is the United States National Phase of PCT ApplicationNo. KR2007/002935 filed 18 Jun. 2007 which claims priority to KoreanPatent Application No. 10-2006-0055549 filed 20 Jun. 2006 each of whichis incorporated herein by reference.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

Not Applicable

INCORPORATION-BY-REFERENCE OF MATERIAL SUBMITTED ON A COMPACT DISC

Not Applicable

BACKGROUND OF THE INVENTION

The present invention relates to an apparatus for dry etching a wafer,and more particularly, to a plasma etching chamber of plasma etching afilm remaining on an edge of a semiconductor wafer and particlesdeposited at a periphery thereof.

A film stacked on a surface of a wafer is typically removed by a plasmaetching. However, during the process, as the stacked film remains,particles are generated. The particles are not completely removed andsome of the particles are deposited at an edge of the wafer.

In order to completely remove the particles deposited at the edge of thewafer, it has been developed a plasma etching chamber wherein upper andlower electrodes having a ring shape are disposed above and below awafer chuck on which the wafer is put, a voltage is applied to both theelectrodes while supplying a reaction gas to the edge of the wafer andplasma is thus generated with which the particles at the edge areremoved.

The known plasma etching chamber comprises a housing having a spaceisolated from an outside, a ring-shaped upper electrode that is disposedat an upper part in the housing to be moveable vertically, a gasdistribution plate that is located on a center of the upper electrodeand forms a passage of a reaction gas, a wafer chuck vertically operatedso that it receives a wafer loaded through a gate and a ring-shapedlower electrode that is disposed at a periphery.

The plasma etching is carried out while maintaining a gap between thegas distribution plate and the wafer surface to be 0.1˜0.6 mm(typically, 0.35 mm). Since the error of the gap is managed in a severcondition of 0.05 mm unit, the gap should be finely adjusted in a veryprecious manner. In addition, the center of the wafer should not bedeviated from a center of the wafer chuck and not be eccentricallyloaded.

In the mean time, in the plasma etching chamber, the reactionby-products are deposited at the upper and lower electrodes and theperiphery of the assembly during the operation. Accordingly, the chamberis periodically disassembled so as to clean.

In the known plasma etching chamber, the upper and lower electrodes areindependently driven vertically and an insulator to support the upperelectrode is supported through a center of an upper cover of thehousing. Accordingly, whenever disassembling and re-assembling thechamber, an alignment of the upper electrode and the assembly adjacentthereto is apt to be varied. Thereby, when disassembling and assemblingthe plasma etching chamber, it is causes a change in the gap between theupper electrode and the wafer surface or a mis-alignment of the wafer.As a result, the gap or alignment should be precisely set again everytime.

Furthermore, it is necessary to check with naked eyes whether the wafer,which is supplied into the housing and put on an upper surface of thewafer chuck, is correctly aligned, prior to the plasma etching. However,since the conventional plasma etching chamber is provided at the centerthereof with a vertically moving rod so as to vertically move the upperelectrode, it is impossible to check the wafer chuck from the above withnaked eyes and thus to monitor the alignment of the wafer from theoutside.

In addition, in the conventional plasma etching chamber, the wafer maybe damaged in the course of chucking and etching the wafer into thechamber and de-chucking the etched wafer.

The wafer chuck is provided with a separate mechanism for chucking andde-chucking the wafer. An example thereof is a vacuum chuck thatvacuum-sucks a lower surface of the wafer when loading the wafer. Inaddition, in etching, the charges are accumulated on the surface of thewafer due to the plasma. The charges may shock the wafer surface todamage the wafer. In particular, a gate film exhibits a property that itis easily damaged by the charges accumulated on the wafer.

In addition, when applying poly-imide as the wafer chuck, there occursno slip when loading and unloading the wafer. However, the poly-imide isapt to be easily damaged by the plasma, so that it is difficult to applyit to the wafer chuck.

BRIEF DESCRIPTION OF THE INVENTION

Accordingly, the present invention has been made to solve the aboveproblems. An object of the invention is to provide a plasma etchingchamber having a structure in which an alignment of upper and lowerelectrodes are not varied even though a cover of a housing isopened/closed so as to clean and repair the chamber.

Another object of the invention is to provide a plasma etching chamberhaving a structure in which an alignment of a wafer can be observed froman upper center of a housing with naked eyes or observation tool.

Still another object of the invention is to provide a plasma etchingchamber capable of eliminating charges to prevent a damage of a wafer byintroducing an electrostatic chuck to a wafer chuck, the charges beingaccumulated on the wafer due to the plasma when etching.

Yet still another object of the invention is to provide a plasma etchingchamber capable of preventing a slip when loading a wafer on a waferchuck.

Another object of the invention is to provide a plasma etching chamberhaving a structure capable of automatically controlling an etching timeof a wafer to suppress an over-etching and allowing an in-situmonitoring.

In order to achieve the above object, there is provided a plasma etchingchamber comprising a housing providing a space isolated from an outsideand having an upper surface opened/closed by a cover; an upper electrodeassembly mounted in the housing with being separated from the cover sothat its position can be maintained when opening and closing the cover;a lower electrode assembly mounted below the upper electrode assembly tobe moveable vertically in the housing; and means for moving the lowerelectrode assembly vertically.

In addition, the lower electrode assembly may comprise a wafer chuck onwhich the wafer rests and a ring-shaped lower electrode that is disposedat a periphery of the wafer chuck. In addition, the wafer chuck may bemade of ceramics and have a space therein in which a center fan formedwith poly-imide is accommodated.

In addition, a ring-shaped discharge electrode grounded via a switchingmeans may be mounted at an edge of the wafer chuck. Here, anelectrostatic electrode to which power is applied through a DC generatormay be disposed in the center fan to chuck or de-chuck the wafer withelectrostatic charges.

In addition, the plasma etching chamber may have an in-situ monitoringtool that is disposed in a vent passage of the housing and detectsparticles remaining in gases generated with the plasma etching. At thistime, the in-situ monitoring tool may comprise a light-emitting part anda light-receiving part that are disposed to be opposite.

In addition, the upper electrode assembly may rest on a step formed on aside wall of the housing and may be fixed with an engagement means.

In addition, the vertically moving means may comprise a shaft downwardlyextending from the lower electrode assembly and protruding to an outsideof the housing; a screw driven by a servo motor; a carrier verticallymoving along the screw as the screw rotates; and a support rodconnecting the shaft and the carrier.

In addition, a sealing may be interposed between the housing and thecover.

In addition, a bellows for maintaining an air-tight state may be furthermounted to a periphery of the shaft.

In addition, in order to achieve the above objects, there is provided aplasma etching chamber comprising: a housing providing a space isolatedfrom an outside and having an upper surface opened/closed by a cover; anupper electrode assembly mounted in the housing; a lower electrodeassembly mounted to be moveable vertically below the upper electrodeassembly in the housing, a wafer resting on the lower electrodeassembly; means for moving the lower electrode assembly vertically; anda transparent observation window provided at a center of the upperelectrode assembly and allowing an alignment of the wafer to be observedfrom the outside.

In addition, a transparent observation window may be further provided ata center of an upper surface of the housing.

In addition, a CCD camera may be further provided above the observationwindow formed on the center of the upper electrode assembly or on thecenter of the upper surface of the housing. In addition, an alignmentmark may be respectively formed on a center of the observation windowand a center of the lower electrode assembly, so that an alignment ofthe upper and lower electrode assemblies can be checked according towhether the alignment marks are matched each other. In addition, thealignment mark may be cross-shaped.

In addition, the transparent material may include quartz or sapphire.

As described above, the plasma etching chamber according to theinvention has the advantages as follows.

First, the upper electrode assembly in the housing is fixed at theposition that is not affected by the opening/closing of the cover andthe minute control is carried out so that the lower electrode assemblyis relatively moved to form a gap necessary for the plasma etching.Accordingly, even though the cover is frequently opened and closed, thearrangement relationship of the upper and lower electrode assemblies isnot changed. In addition, it is possible to carry out the super-precisecontrol of sub-millimeter unit through the vertical movement of thelower electrode assembly.

Second, contrary to the prior art, the driving means for verticallymoving the upper electrode assembly can be omitted, so that a simplestructure can be realized.

Third, since the upper electrode assembly can be easily removed throughthe cover, it is possible to easily clean the upper electrode body, thegas distribution plate and the wafer chuck after the use.

Fourth, since the inside of the housing can be observed with naked eyesor a proper observation device such as CCD camera, as required, it ispossible to eliminate the defective factor due to the mis-alignmentbefore the etching.

Fifth, the wafer chuck having the inside made of poly-imide and theperiphery made of ceramics prevents the slip when loading the wafer,thereby realizing a precise alignment and preventing the wafer damagedue to the plasma. In addition, since the inexpensive poly-imide isused, it is possible to reduce the manufacturing cost.

Sixth, since it is possible to check whether the particles remain in thedischarged gas and to analyze the components of the discharged gas withthe in-situ monitoring tool and it is possible to automatically controlthe plasma etching time, the over-etching can be prevented.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other objects, features and advantages of the presentinvention will be more apparent from the following detailed descriptiontaken in conjunction with the accompanying drawings, in which:

FIG. 1 is a sectional side view of a plasma etching chamber according toan embodiment;

FIG. 2 is a plan view of a plasma etching chamber according to anembodiment;

FIG. 3 shows that a CCD camera is mounted to an observation window of acover shown in FIG. 1;

FIG. 4 is a sectional side view of a plasma etching chamber showing astate after a wafer chuck is elevated;

FIG. 5 is a sectional view of a wafer chuck according to anotherembodiment of the invention; and

FIG. 6 shows an example of an arrangement of an in-situ monitoring toolof a plasma etching chamber according to an embodiment of the invention.

DETAILED DESCRIPTION OF THE INVENTION

Hereinafter, a preferred embodiment of the present invention will bedescribed with reference to the accompanying drawings. In the followingdescription of the present invention, a detailed description of knownfunctions and configurations incorporated herein will be omitted when itmay make the subject matter of the present invention rather unclear.

FIG. 1 is a sectional side view of a plasma etching chamber according toan embodiment, FIG. 2 is a plan view of a plasma etching chamberaccording to an embodiment, FIG. 3 shows that a CCD camera is mounted toan observation window of a cover shown in FIG. 1 and FIG. 4 is asectional side view of a plasma etching chamber showing a state after awafer chuck is elevated.

Referring to FIG. 1, a plasma etching chamber according to an embodimentof the invention comprises a housing providing a space isolated from anoutside and having an upper surface opened/closed by a cover 4.

The cover 4 is connected to the housing 2 by a typical means. Forexample, it may be adopted a direct engagement manner using a bolt and anut or a manner using a clamp means. A sealing 6 such as O-ring ispreferably interposed between the housing 2 and the cover 4.

At an upper part of the housing 2, an upper electrode assembly 8 isdisposed which is exposed to an outside when the cover 4 is opened. Theupper electrode assembly 8 comprises an upper electrode body 80 made ofa conductor detachably mounted in the housing 2, an upper electrode 81fixedly attached to a bottom surface of the upper electrode body 80 anda gas distribution plate 82 located at an inner side thereof and made ofan insulator.

A reaction gas passage 84 is formed between the upper electrode 81 andthe gas distribution plate 82, which introduces reaction gas, which issupplied from the reaction gas plate 83, to an edge of a wafer W. Inaddition, an inert gas passage 86 for introducing inert gases such asnitrogen, helium and the like supplied from the inert gas pipe 85 isformed at a bottom surface adjacent to a center of the gas distributionplate 82 within a predetermined range by a baffle plate 87. Both the gaspassages 84, 86 may be formed to have a circular shape in plan view.

In the mean time, the reaction gas pipe 83 and the inert gas pipe 85 maybe detachably attached to inlets of the corresponding gas passages 84,86 through adapters 88, 89, respectively. With the detachable structureof the adapters 88, 89, the upper electrode assembly 8 can be easilyseparated from the housing 2.

More preferably, the inert gas may be introduced into the inert gaspassage 86 without the inert gas pipe 85 and the adapter 89. To thisend, separate horizontal passages that communicate with the inert gaspassage 86 are provided to a sidewall of the housing 2 and the upperelectrode body 80. Thereby, the inert gas is directly introduced intothe inert gas passage 86 through the housing 2 and the upper electrodebody 80.

In addition, the reaction gas can be also introduced into the reactiongas passage 84 without the reaction gas pipe 83 and the adapter 88. Tothis end, an introduction hole through which the reaction gas isintroduced is formed at an upper sidewall of the housing 2. Through theintroduction hole, the reaction gas is directly introduced to the insidespace of the housing 2. The introduced reaction gas is allowed to flowinto the reaction gas passage 84 through a vertical passage.

To a bracket 12 of the housing 2 is mounted an engagement means 10 thatdetachably fixes the upper electrode assembly 8.

The engagement means 10 may take any shape as long as it preciselypositions and fixes the upper electrode body 80. For example, a step 12for supporting the upper electrode body 80 is formed at a position ofthe sidewall of the housing 2 and the upper electrode body 80 resting onthe step 12 is vertically fixed with a bolt or pin. In the mean time, athrough-hole into through the bolt or pin passes is formed at acorresponding part of the upper electrode body 80. In order to the fixthe upper electrode body 80, a nut is used for the bolt and a clamp isused for the pin.

In addition, a diameter of the through-hole through which the bolt orpin passes may be larger than that of the bolt or pin, so as to secure agap capable of adjusting an alignment when fixing the upper electrodebody 80.

A vertically moving means 14 is disposed at a side of the housing 2. Thevertically moving means 14 comprises a screw 141 disposed to passbetween a pair of shaft bearing parts 141, a servo motor 142 forprecisely rotation-driving the screw 141 and a carrier 143 that goes upand down as the screw 141 is spirally rotated.

At a lower part of the upper electrode assembly 8 is located a lowerelectrode assembly 16 that vertically moves by the vertically movingmeans 14.

The lower electrode assembly 16 comprises a wafer chuck 160 that isdisposed to be opposite to the gas distribution plate 82 and isvertically moved and a ring-shaped lower electrode 161 that is attachedto a periphery of the wafer chuck 160 in an insulating manner and isdisposed to be opposite to the ring-shaped upper electrode 81. The waferchuck 160 is mounted on an upper surface of a mounting plate 163 via aninsulation plate 162.

To a bottom center of the mounting plate 163 is fixed a shaft 164extending to the outside. A longitudinal end of the shaft is integrallyconnected, in an orthogonal direction, to a support rod 144 extendingfrom the carrier 143. A bellows 165 is provided to a surrounding of theshaft 164, so that an air-tight state can be maintained during thevertical movement.

At a side of the housing 2, a vent passage 20 that is opened and closedby a gate valve 18 is extended. To a longitudinal end of the ventpassage is provided a dry pump 22, so that the reaction gas and inertgas supplied to the housing 2 and the particles generated by the etchingare collected. In addition, to a side of the housing 2 is provided anopenable slot valve 24 that is used as a passage when loading orunloading a wafer W to or from an upper surface of the wafer chuck 160.To a lower end of the upper electrode 81 are attached a gap sensor 26for light reception and a gap sensor 28 for light emitting, which aredisposed to be opposite to each other.

The gap sensor 26 for light reception may include a CCD camera and thegap sensor 28 for light emitting may include a short wavelength lamp orlaser setter having a better directionality of emitted light.

To a center of the cover 4 is provided an observation window 30 made oftransparent material such as quartz or sapphire. To a center of theupper electrode assembly 8 is also provided an observation window 90.The observation windows 30, 90 are concentrically disposed.

At centers of the observation windows 30, 90 are indicated alignmentmarks 32, 92 such as cross shape (+), as shown in FIG. 2. Thus, it ispossible to correctly check a center alignment of the wafer W with nakedeyes and the like. In the mean time, the shape of the alignment mark maybe diversely modified.

As another example for the observation, as shown in FIG. 3, a CCD camera34 may be integrally mounted to the observation window 30 provided tothe housing 2. Thereby, an alignment state of the wafer W loaded on thewafer chuck W is enlarged with a separate monitor, so that it ispossible to check the alignment state in a more precise manner. Inaddition, it is possible to check the alignment state in a manner ofsynthesizing images photographed by the CCD camera 34 and calculating anerror.

In addition, it is possible to check the alignment state through theobservation window 32 while loading a wafer for alignment check havingan alignment mark of a cross shape indicated at the center thereof onthe wafer chuck 160 in the same condition as the real operation. At thistime, when there occurs an error, it is possible to adjust an alignmentof the wafer in a manner of adjusting a position or operation range of ahandler (not shown) transferring the wafer W.

The plasma etching chamber having the structure as described above isoperated according to following sequences.

First, the center alignment state of the wafer W located on the waferchuck 160 can be observed with naked eyes or CCD camera 34 through theobservation window 30 mounted at the upper center of the cover 4 and theobservation window 90 mounted to the center of the upper electrodeassembly 8. Therefore, it is possible to take a measure the waferabnormally loaded, before the etching, thereby reducing a defectiveproportion. In the mean time, when the cover 4 of the housing 2 isopened, it is possible to easily disassemble and assemble the upperelectrode assembly from and to the housing 2.

When the center alignment of the wafer W is checked, the verticallymoving means 14 elevates the lower electrode assembly 16 up to apredetermined location, so that the upper electrode 81 and an edgesurface of the wafer are opposed with a gap.

During the process, the light from the gap sensor 28 for light emittingmounted at the side of the housing 2 is shaded by the wafer W of thelower electrode assembly 16 being elevating, thereby causing a change ina quantity of light. Thereby, the gap sensor 26 for light receptiontransmits a signal of detecting a decrease in the quantity of light. Thesignal is a control signal that is fed back to the servo motor 142 tocontrol the rotation driving of the motor. In other words, the servomotor 142 is stopped with the detection signal from the gap sensor 26for light reception, so that the upper electrode 81 is opposed to theedge upper surface of the wafer W with a predetermined gap.

According to the subsequent processes of the invention, the reaction gasis introduced to the edge of the wafer W to cause a plasma discharge andthe inside of the wafer is left as a non-discharge area while beingprotected by the inert gas, so that only the edge of the wafer W isetched. The etching process for the edge of the wafer W is well known inthe art, so that its detailed descriptions are omitted.

FIG. 5 is a sectional view of a wafer chuck according to anotherembodiment of the invention, and FIG. 6 shows an example of anarrangement of an in-situ monitoring tool of a plasma etching chamberaccording to an embodiment of the invention.

Meanwhile, in the plasma etching chamber according to an embodiment ofthe invention, the wafer chuck 160 is typically made of ceramics.Referring to FIG. 5, the wafer chuck 160 is formed to have a spacetherein in which a center fan 166 separately made of poly-imide isfitted. The poly-imide applied to the center fan 166 has a high surfacefriction efficient. Therefore, when the wafer W is put on an uppersurface of the center fan, there occurs no slip. Thereby, it is possibleto actively suppress the alignment defective occurring when loading thewafer W and to reduce the manufacturing cost of the wafer chuck 160.

In addition, since the poly-imide has a property that is apt to bedamaged by the plasma, the wafer chuck 160 is not made of poly-imidematerial over the entire thereof. In other words, as shown in FIG. 5,the outer surface edge and the bottom surface of the wafer chuck 160contacting the plasma are made of ceramics and the inner part of thewafer, which does not contact the plasma, is made of poly-imide.

In addition, in the plasma etching chamber according to an embodiment ofthe invention, the wafer chuck 160 may consist of an electrostaticchuck. In this case, a ring-shaped discharge electrode 167 is furtherprovided to the upper surface edge of the wafer chuck 160 andelectrostatic electrodes 168 are spirally disposed in the center fan166.

The edge of the wafer chuck 160 is set to have a width L of 10 mm ormore so that the discharge electrode 167 is accommodated with asufficient gap with the electrostatic electrodes 168. The dischargeelectrode 167 is grounded via a switching means 169 and a DC generator170 is connected to the electrostatic electrodes 168.

While the charges electrified with the electrostatic electrodes 168 forman electrostatic field, the wafer chuck 160 serves as an electrostaticchuck chucking or de-chucking the wafer W. More specifically, inchucking, the DC generator 170 electrifies the electrostatic electrodes168 with positive charges, which have a polarity opposite to the chargesof the wafer W, to form an electrostatic field of the positive polarity,thereby chucking the wafer W with a strong sucking force of the oppositepolarity. To the contrary, in de-chucking, the DC generator 170electrifies the electrostatic electrodes 168 with negative charges,which have a polarity same as the charges of the wafer W, therebyde-chucking the wafer W with a strong repulsive force of the samepolarity.

In addition, the arrangement shape of the electrostatic electrode 168 isnot limited to the spiral form.

During the chucking/de-chucking process, some of the charges applied tothe electrostatic electrodes 168 are accumulated to the upper surfacethrough the center fan 166. Due to the accumulated charges, the oppositebottom surface of the wafer W is electrified with the charges having theopposite polarity. Such phenomenon increases the force of chucking thewafer or serves as a force of interfering with the de-chucking.

Accordingly, when the plasma etching is completed, the switching means169 is turned on to make the charges electrified in the bottom surfaceof the wafer W flow to the discharge electrode 167. The switching means169 should be converted into a switching-off state just before theplasma etching starts. At the same time, the DC generator 170 appliesthe voltage, which is converted into a polarity opposite to the powerapplied up to now, to the electrostatic electrode 168, therebyelectrifying it with the negative charges that have a polarity oppositeto the positive charges electrified up to now. As a result, the uppersurface of the center fan 166 is neutralized, so that there occurs noproblem due to the remaining of the charges.

In addition, a means for automatically controlling an etching time maybe provided to the plasma etching chamber according to an embodiment ofthe invention.

FIG. 6 shows an example of an in-situ monitoring tool 40 having astructure that a light-emitting part 36 and a light-receiving part 38are disposed to be opposite to each other on the vent passage 20 so asto automatically control an etching time.

The in-situ monitoring tool 40 is a device that the light-receiving part38 receives the light emitted from the light-emitting part 36 and thenconverts it into an electric signal. In other words, when the gas, whichwill be discharged through the vent passage 20, contains a largequantity of particles, the light emitted from the light-emitting part 36is spectrally refracted and scattered, so that the quantity of lightdetected by the light-receiving part 38 is increased or decreased. Basedon the change in the electric signal as the quantity of light is varied,the etching time is controlled. The in-situ monitoring tool 40 is notmounted only to the vent passage 20. For example, even when it isdisposed side in line at the sides of the gap sensor 26 for lightreception and the gap sensor 28 for light emitting, it is possible tocheck whether the particles remain and to control the etching time,through the gas flow between the upper electrode 81 and the uppersurface of the wafer W.

By controlling the etching time, it is possible to prevent the wafersurface from being over-etched due to the plasma.

While the invention has been shown and described with reference tocertain preferred embodiments thereof, it will be understood by thoseskilled in the art that various changes in form and details may be madethereto without departing from the spirit and scope of the invention asdefined by the appended claims.

1. A plasma etching chamber comprising: a housing providing a spaceisolated from an outside and having an upper surface opened and closedby a cover; an upper electrode assembly mounted in the housing withbeing separated from the cover so that its position is maintained whenopening and closing the cover; a lower electrode assembly mounted belowthe upper electrode assembly to be moveable vertically in the housing, awafer resting on the lower electrode assembly; and means for moving thelower electrode assembly vertically.
 2. The plasma etching chamberaccording to claim 1, wherein the lower electrode assembly comprises awafer chuck on which the wafer rests and a ring-shaped lower electrodethat is disposed at a periphery of the wafer chuck.
 3. The plasmaetching chamber according to claim 1, wherein the lower electrodeassembly comprises a wafer chuck on which the wafer rests, and the waferchuck is made of ceramics and has a space therein in which a center fanformed with poly-imide is accommodated.
 4. The plasma etching chamberaccording to claim 2, wherein a ring-shaped discharge electrode groundedvia a switching means is mounted at an edge of the wafer chuck, and anelectrostatic electrode to which power is applied through a DC generatoris disposed in the center fan to chuck or de-chuck the wafer withelectrostatic charges.
 5. The plasma etching chamber according to claim1, further comprising an in-situ monitoring tool that is disposed in avent passage of the housing and detects particles remaining in gasesgenerated with the plasma etching, wherein the in-situ monitoring toolcomprises a light-emitting part and a light-receiving part that aredisposed to be opposite.
 6. The plasma etching chamber according toclaim 1, wherein the upper electrode assembly rests on a step formed ona side wall of the housing and is fixed with an engagement means.
 7. Theplasma etching chamber according to claim 1, wherein the verticallymoving means comprises a shaft downwardly extending from the lowerelectrode assembly and protruding to an outside of the housing; a screwdriven by a servo motor; a carrier vertically moving along the screw asthe screw rotates; and a support rod connecting the shaft and thecarrier.
 8. The plasma etching chamber according to claim 1, wherein asealing is interposed between the housing and the cover.
 9. The plasmaetching chamber according to claim 1, wherein a bellows for maintainingan air-tight state is further mounted to a periphery of the shaft. 10.The plasma etching chamber according to claim 1, wherein the upperelectrode assembly comprises an upper electrode body detachably mountedin the housing, a ring-shaped upper electrode fixedly attached to abottom surface of the upper electrode body, a gas distribution plateforming a reaction gas passage at an inner side of the upper electrode,and a baffle plate forming an inert gas passage at a bottom surface ofthe gas distribution plate.
 11. The plasma etching chamber according toclaim 10, wherein horizontal passages that communicate with the outsideand the inert gas passage are provided to a sidewall of the housing andthe upper electrode body.
 12. The plasma etching chamber according toclaim 10, wherein an introduction hole through which the reaction gas isintroduced is formed at an upper sidewall of the housing and thereaction gas is directly introduced to the reaction gas passage througha vertical passage formed at the upper electrode body.
 13. The plasmaetching chamber according to claim 6, wherein the engagement meanscomprises a bolt or a pin, and a through-hole through which the bolt orpin passes is formed at the upper electrode assembly, and a size of thethrough-hole is larger than that of the bolt or pin.
 14. A plasmaetching chamber comprising: a housing providing a space isolated from anoutside and having an upper surface opened and closed by a cover; anupper electrode assembly mounted in the housing; a lower electrodeassembly mounted below the upper electrode assembly to be moveablevertically in the housing, a wafer resting on the lower electrodeassembly; means for moving the lower electrode assembly vertically; anda transparent observation window provided at a center of the upperelectrode assembly.
 15. The plasma etching chamber according to claim14, wherein a transparent observation window is further provided at acenter of an upper surface of the housing.
 16. The plasma etchingchamber according to claim 14, wherein a CCD camera is further providedabove the observation window formed on the center of the upper electrodeassembly.
 17. The plasma etching chamber according to claim 15, whereina CCD camera is further provided above the observation window formed onthe center of the upper surface of the housing.
 18. The plasma etchingchamber according to claim 14, wherein an alignment mark is respectivelyformed on a center of the observation window and a center of the lowerelectrode assembly, so that an alignment of the upper and lowerelectrode assemblies is checked according to whether the alignment marksare matched each other.
 19. The plasma etching chamber according toclaim 18, wherein the alignment mark is cross-shaped.
 20. The plasmaetching chamber according to claim 14, wherein the transparent materialincludes quartz or sapphire.
 21. The plasma etching chamber according toclaim 3 wherein a ring-shaped discharge electrode grounded via aswitching means is mounted at an edge of the wafer chuck, and anelectrostatic electrode to which power is applied through a DC generatoris disposed in the center fan to chuck or de-chuck the wafer withelectrostatic charges.